data = "firstName and favoriteFood"
mandatory_fields = ['firstName', 'lastName', 'age']


# for each
for field in mandatory_fields:
    if field not in data:
        print("Error, missing req field {0}".format(field));

# still fine, multiple if statements
if ('firstName' not in data or 
    'lastName' not in data or
    'age' not in data):
    print("Error, missing a req field");

# not very readable, list comprehension
missing_fields = [x for x in mandatory_fields if x not in data]
if (len(missing_fields)>0):
    print("Error, missing fields {0}".format(", ".join(missing_fields)));

如果你想要的只是True或False, any()是目前为止最好的方法，但如果你想知道具体匹配哪个字符串/字符串，你可以使用一些东西。

如果你想要第一个匹配(默认为False):

match = next((x for x in a if x in str), False)

如果你想获得所有匹配项(包括重复项):

matches = [x for x in a if x in str]

如果你想获得所有非重复的匹配(不考虑顺序):

matches = {x for x in a if x in str}

如果你想按正确的顺序获得所有非重复的匹配项:

matches = []
for x in a:
    if x in str and x not in matches:
        matches.append(x)

如果a或str中的字符串变长，您应该小心。简单的解决方案是O(S*(A^2))，其中S是str的长度，A是A中所有字符串长度的总和。要获得更快的解决方案，请查看用于字符串匹配的Aho-Corasick算法，该算法在线性时间O(S+A)内运行。

python文档中推荐的regex模块支持这一点

words = {'he', 'or', 'low'}
p = regex.compile(r"\L<name>", name=words)
m = p.findall('helloworld')
print(m)

输出:

['he', 'low', 'or']

实现的一些细节:link

在另一个字符串列表中查找多个字符串的一种紧凑方法是使用set.intersection。这比大型集或列表中的列表理解执行得快得多。

>>> astring = ['abc','def','ghi','jkl','mno']
>>> bstring = ['def', 'jkl']
>>> a_set = set(astring)  # convert list to set
>>> b_set = set(bstring)
>>> matches = a_set.intersection(b_set)
>>> matches
{'def', 'jkl'}
>>> list(matches) # if you want a list instead of a set
['def', 'jkl']
>>>

这是set的另一个解。使用set.intersection。对于一行代码。

subset = {"some" ,"words"} 
text = "some words to be searched here"
if len(subset & set(text.split())) == len(subset):
   print("All values present in text")

if subset & set(text.split()):
   print("Atleast one values present in text")